Mounting for electrical apparatus



H. A. BREDEHOFT MOUNTING FOR ELECTRICAL APPARATUS April 27, 1943.

Filed March 5, 1942 A TTORNEV /NvsNo/Q V H A. BRE DE HOF A .9v l u Patented Apr. 27, 1943 U N ITE-D STATES PAT ENT O ICE.

MOUNTING FOR/l ELECTRICAL APPARATUS.

Harold A. Bredelioft', Millington, N. J., assi'gnor-to Bell Telephone Laboratories,

Incorporate'di New York, N. Y., a corporation of`New--York Application March: 5, 1942, Serial No..433',481

6 Claims. (Cl. 17-'1"-7)r This invention relates tov mountingsfor. electrical apparatus and particularly. tol improvements. in` telephone ringer mountings.

In the mountings of electrical devices,.particu larly such devices whichare utilized in telephone: systems andV are located at a subscribers' station,.the space available is generally'ofa limited area with the result thatdiiculty is frequently experienced in.` attaching a: device,V such. as a. telephone ringer, to its support, and also'in. detaching it therefrom. In what isv commonly known as the combined telephone set, the.v telephone ringer isattached to. a bracket secured'to the base of the telephone set by means of screws, which. of necessity are relatively short. The attaching screws. pass through suitable holesin' the gong-supporting element ofthe-ringerstructure and arethen screwedi into tapped. holes.Y in the bracket. Owing. to the relatively short length of the screws andthe confined area available in which to work onV the screwsVdi'iculty has been encountered in aligning the. holes'k of the` ringer structure with those oi the. supporting base: and in then inserting the screws therein to. be screwed so as to' fasten the. ringer to the base. Similarly, when the ringer is tok be. removed from. its support, the screws, though readily accessible to a screwv driver; invariably drop out of the` holes when unscrewed therefrom, fall', andare lost.`

Itis the object of this. invention to. facilitate the mounting. and' rem-oval of an electrical. devicev on, and' from a supporting. member to which the device is adapted to be aixed. by means.l of screws.

Thisobject is attained in accordance. with.` a feature of the invention by the provision of a screw suspension, or retaining device which. is permanently xed to the device to be mounted, and which functions to hold the mounting screws on the device when thelatter is`A removed from its support, in such. a manner that. the screwsl are held in communication with theirirespectivel holes in the device, andlinl readiness to be screwed into their respective tapped. holes in the'support when the holes. of the device and. support are'v brought into alignment.

In accordancewithv another feature of the invention, the screw retaining.' device comprises a leaf springlxed at its-mid-pointto thedevic'e to -be mounted,.andhasits two ends pretensioned, or preflexed in. such. a manner that when; the screws, which secure the electrical deviceto its support, are screwed. outof their respective holes inthe support, the spring ends vfunctionV to withdraw the screws from'the supportv holes andt'o retain them partially inserted in their respective holes vin. the electrical device.

A further feature of the inventionresides inso proportioning the dimensions of. the screwsand f their respective holesin the'retaining devicethat whenithe.n screws are Withdrawn from` their respectiveY holes inthe support, they are. held against accidental detachment from the. electrical device by the screw retaining device..

These and other features of the'invrention will be readilyunderstood from the followingdetailed description made with reference to` the accompanying drawing in which.:

Fig. 1 isza plan View' ofthe interior. of' the base of a combined telephone set showing severallel'ectrical devices.. including. a telephone ringer mounted-thereon; l

Fig. 2 is a` sectional view taken alongtheline. 2-2 of Fig. 1 and lookingvinlthe direction of the arrows;

Fig. 3 is aview of the gong..supporting bracket of the: ringer shown in Figs. l; and 2, and shows` the-screws; which secure theringer to its. support, in the` positions iny which they are. held by the screw-retaining, device when theringer is detached romthe support;

Fig. 41 is a view taken along the line l-4'. of Fig. 2looking inthe directionof the arrows; and

Fig, 5 is a view of one ofthey screws employed in securing` the ringer toits support.. and. illustrates the particular designof the shankthereof.

In Fig.. 1, the base ll.- isthat of acombined telephone handset which serves tosupport the telephone substation-apparatus,- suchas the ringer 9, induction` coil 8y and' condenser 'Lv The ringer, the mounting of which on the. base. Il is concerned with the present invention may be of any suitable design, such for example, as"A the design disclosedv in H.. A'. Bredehoit Patent No. 2,082,695; issued June l;` 1937.

Referring particularly. tov Fig. 2 the ringer perise, which is similar to: the ringer described inthe above-identified patent, is shown mounted on a. substantially triangularl shaped bracket.- l0 which,l in turn, is'xedfto the basev I'I- of the telephone handsetV by'meansl of: three eyeletsl and a corresponding number; of? rubber grommets through. which the eyelets extend. The three eyelet-gr'ommet assemblies are disposed in triangular relation, there. being onelocated at.y the narrow end of the bracket l0 and twoothers spaced from one another andi located near. the outer corners; of-li the widerend ofv the bracket. These latter two:l eyelets liz. and; grommets 'la are clearly shown in Fig. 4. This particular type of support for the bracket I lends resiliency to the ringer mounting.

The ringer yoke I4 is provided with two integrally formed right-angle extensions I5 and I6, to the extremities of each of which is secured a ringer gong I1. These gongs are provided with eccentric holes which accommodate the screws I8. The eccentricity referred to provides means for adjusting the position of the gong edges with respect to the clapper 20, thereby furnishing a desirable method of adjusting the ringer volume. The extensions I5 and I6 are integrally joined to provide a fiat portion 2 I which is provided with two untapped holes 22. The bracket I0 is provided with two tapped holes 23 which are spaced from one another a distance corresponding to the spacing of the holes 22. The yoke I4 supports the ringer coils 24 by means of screws 25 which are screwed into tapped holes in the core members 26.

The screws 21 serve to secure theringer structure to the bracket I0.- A `substantially V-shaped spring 28 has its mid-point riveted to the rightangle extension of the yoke III at a point midway between the two holes 22 and is preflexed, or pretensioned so as to normally assume the configuration shown in Fig. 3. Near each end yof the spring 28 is located a hole 29 of slightly smaller diameter than the thread-bearing portion of the screws 21. Between the thread-bearing portion of each of the screws 21 and their respective heads is a shank portion of smaller diameter than the thread-bearing portion. It is apparent that the screws 21 may be screwed into the holesy 29 of the spring 23 with a little effort, and once screwed therein to the positions shown in Figs. 3 and 5 cannot become accidentally detached from the spring.

Prior to attaching the ringer structure to the bracket I0, the screws 21 and their retaining spring 28 assume the positions shown in Fig. 3, in which the screws are held partially inserted in the holes 22. When the ringer is to be mounted on the bracket I0, the ringer is positioned so as to bring the holes 22 of the ringer structure into alignment with the holes 23 of the bracket IU and, by means of a screw driver, the screws are screwed into the tapped holes 23. When the screws 21v are fully screwed into their respective holes in the bracket I0, the spring 28 assumes the ilat Position shown in Fig. 4. The lock washer 30 interposed between the head of each screw 21 and the spring 28 serves a well-known purpose.

When the ringer is to be removed from the bracket I0, a screw driver is applied to the heads of screws 21 and the screws are screwed out of their respective tapped holes 23 in bracket I0. As the screws are disengaged from the holes 23 by unscrewing, the spring 28, in tending to resume its normal shape, shown in Fig. 3, acts upon the screws and withdraws them into the holes 22 of the ringer structure as soon as the pressure exerted by the screw driver is removed. By virtue of the fact thatthe diameter of the holes 29 in the retaining spring is smaller than the diameter of the screw thread, the screws cannot accidentally become detached from the spring, -so that the screws are held in the position shown in Fig. 3, and the ringer structure may be removed from the bracket I0 with the screws fixed thereto.

The adjustment of the spring tension is such that the screws are not lifted clear of the holes 22 inthe ringer structure, but are held with their threaded ends partially inserted in the holes 22, thus they are retained in a position which facilitates the remounting of the ringer on the bracket. When it is necessary to mount the ringer on the bracket I0, all that is required is that the holes 22 of the ringer be brought into alignment with corresponding holes 23 of the bracket I0 which automatically positions the screw ends opposite their respective tapped holes 23 of the bracket. A screw driver is then applied to the screw-heads and the screws are screwed into their respective holes 23 to securely fix the ringer on the bracket.

By virtue 'of the screw-retaining device described, the screws which serve to secure the y ringer on its mounting bracket are always held in a position on the ringer such as to facilitate and expedite the mounting of the ringer on the bracket, and the difficulties heretofore encountered in mounting and detaching the ringer are obviated.

What is claimed is:

1..In combination, a support having a pair of tapped holes, a device to be secured to said support having a pair of untapped holes, the holes of said support and of said device adapted to be brought into alignment when said device is to be secured to' said support, a screw passing through each pair of aligned holes and adapted to be screwed into its respective tapped hole in said support to secure said device to said support, and means effective when said screws are screwed out of `their respective tapped holes in said bracket for withdrawing the screws part way out of their respective holes in said device.

2. In combination, a device, screws for attaching said device to a support, and means for supporting said screws on said device comprising a substantially V-shaped leaf spring xed at its mid-point to said device and having each portion thereof, which extends from the point of attachment to the device, apertured to receive a screw, the apertures in said spring having a smaller diameter than the diameter of the screws.

3. In combination, a device having a pair of untapped holes, screws for attaching said device to a support, and means for supporting said screws on said device so that the screw-ends are normally located in the untapped holes of said device, comprising a flat spring having its midpoint fixed to said device at a point mid-way between the untapped holes of said device and having each portion thereof which extends from its point of attachment of said device ilexed, so as to be angularly spaced from the untapped holes in said device, and each spring portion having an aperture, for receiving a screw, of lesser diameter than the diameter of the screw.

4. In combination, a device, a support for said device, means for attaching said device to said support comprising a pair of screws, and means for maintaining said screws attached to said device when said device is detached from said support, comprising ak spring fixed at its mid-point to said device and having a hole for the screws near each end thereof of such diameter relative to the diameter of said screws as to maintain said screws loosely fixed to said spring.

5.V In combination, a mounting bracket having a tapped hole, a device to be secured to said bracket having an untapped hole, the hole of said bracket and of said device adapted to be brought into alignmentwhen said device is to be secured to said bracket, a screw passing through the aligned holes and Yadapted to bescrewed into the tapped holegin said bracket s o as to secure said device to said bracket, and means effective when said screw is screwed out of the tapped hole in said bracket for automatically withdrawing it part way into the untapped hole in said device, and for maintaining the screw in such position during the removal of the device from the bracket.

6. In combination, a device to be screwed to a support by means of screws which pass through untapped holes in said device and are screwed into tapped holes in the support, and means for supporting the screws on said device in such a position as to facilitate the attachment of said device to the support, comprising a at spring which is preexed so as to assume, substantially, a V-shape, and has its midpoint xed to said device so as to locate the ends of the` inclined portions thereof spaced from and in superposed relation to the untapped holes in said device, and each portion thereof havingan aperturefor receiving a screw, and each screw having a shank construction such that a threaded portion thereof is of greater diameter than the diameter of the apertures in said spring and is spaced from the screw head by a shank portion of lesser diameter than the apertures in said spring, whereby the screws are loosely held by said spring against accidental detachment therefrom after the threaded portions thereof have been screwed past the spring apertures.

HAROLD A. BREDEHOFT. 

